Hydrodynamic modelling and characterisation of a shallow fluvial lake: a study on the Superior Lake of Mantua

This paper presents a numerical modelling framework developed to simulate circulations and to generally characterise the hydrodynamics of the Superior Lake of Mantua, a shallow fluvial lake in Northern Italy. Such eutrophied basin is characterised by low winds, reduced discharges during the summer and by the presence of large lotus flower (Nelumbo nucifera) meadows, all contributing to water stagnation. A hydrodynamic numerical model was built to understand how physical drivers shape basic circulation dynamics, selecting appropriate methodologies for the lake. These include a 3D code to reproduce the interaction between wind and through-flowing current, a fetch-dependent wind stress model, a porous media approach for canopy flow resistance and the consideration of wave-current interaction. The model allowed to estimate the circulation modes and water residence time distributions under identified typical ordinary, storm and drought conditions, the hydrodynamic influence of the newly-opened secondary outlet of the lake, the surface wave parameters, their influence on circulations and the bottom stress they originate, and the adaptation time scales of circulations to storm events. Some probable effects of the obtained hydrodynamic characteristics of the Superior Lake of Mantua on its biochemical processes are also introduced

Model simulations of the ecological dynamics induced by climate and nutrient load changes for deep subalpine Lake Maggiore (Italy/Switzerland)

Climate warming affects lake ecosystems both through its direct effect on the phenology of species and through the alteration of the physical and chemical environments, which in turn affect community composition. In deep lakes, stratification enhancement and mixing reduction have already been observed, leading to hypolimnetic anoxia and to the rise of cyanophytes. The increase in stability depends on the rise of air temperature due to global emissions of greenhouse gases (GHG). Primary production could then either increase with rising epilimnetic temperature and buoyancy or decrease as fewer nutrients are upwelled from deep layers. The prevailing outcome, as well as the quantitative and temporal dynamics of all climate-induced modifications, depend on the specific lake characteristics. Individual analyses are then needed, one-dimensional coupled hydrodynamic-ecological numerical models being suitable tools for such predictions. Here, we simulated with GLM-AED2 (General Lake Model – Aquatic EcoDynamics) the 2020-2085 dynamics of the oligomictic and oligotrophic deep subalpine Lake Maggiore (Italy/Switzerland), according to the Swiss Climate Change Scenarios CH2011. Multiple realisations were performed for each scenario with random meteorological series obtained from the Vector-Autoregressive Weather Generator (VG), highlighting the uncertainties related to meteorology. Increase and decrease of nutrient loads were also tested. Results show that anoxia would occur in the hypolimnion regardless of nutrient input reduction, unless global GHG emissions were immediately reduced. Total phytoplankton biomass would be weakly affected by climate change, strongly depending on nutrient input, yet water warming would cause cyanophytes to compete with diatoms. Therefore, the fate of Lake Maggiore would be tied to both global and local environmental policies

Pentamethylcyclopentadienyl osmium complexes that contain diazoalkane, dioxygen and allenylidene ligands: preparation and reactivity

Diazoalkane complexes [Os(η5-C5Me5)(N2CAr1Ar2)(PPh3){P(OR)3}]BPh4 (1, 2) [R = Me (1), Et (2); Ar1 = Ar2 = Ph (a); Ar1 = Ph, Ar2 = p-tolyl (b); Ar1Ar2 = C12H8 (fluorenyl) (c)] were prepared by reacting bromo-compounds OsBr(η5-C5Me5)(PPh3){P(OR)3} with an excess of diazoalkane in ethanol. The treatment of diazoalkane complexes 1 and 2 with acetylene under mild conditions (1 atm, RT) led to dipolar (3 + 2) cycloaddition affording 3H-pyrazole derivatives [Os(η5-C5Me5)(η1-[upper bond 1 start]N[double bond, length as m-dash]NC(C12H8)CH[double bond, length as m-dash]C[upper bond 1 end]H)(PPh3){P(OR)3}]BPh4 (6, 7) [R = Me (6), Et (7)] whereas reactions with terminal alkynes R1C[triple bond, length as m-dash]CH (R1 = Ph, p-tolyl, COOMe) gave vinylidene derivatives [Os(η5-C5Me5){[double bond, length as m-dash]C[double bond, length as m-dash]C(H)R1}(PPh3){P(OR)3}]BPh4 (8b–d, 9b–d) [R = Me (8), Et (9); R1 = Ph (b), p-tolyl (c), COOMe (d)]. Exposure to air of dichloromethane solutions of complexes 1 and 2 produced dioxygen derivatives [Os(η5-C5Me5)(η2-O2)(PPh3){P(OR)3}]BPh4 (10, 11) [R = Me (10), Et (11)]. Allenylidene [Os][double bond, length as m-dash]C[double bond, length as m-dash]C[double bond, length as m-dash]CR1R2 (12–14) [R1 = R2 = Ph (12, 13); R1 = Ph, R2 = Me (14)], vinylvinylidene [Os][double bond, length as m-dash]C[double bond, length as m-dash]C(H)C(Ph)[double bond, length as m-dash]CH2 (15) and 3-hydroxyvinylidene [Os][double bond, length as m-dash]C[double bond, length as m-dash]C(H)C(H)R2(OH) (16, 17) [R2 = Ph (16), H (17)] derivatives were also prepared. The vinylidene complex [Os(η5-C5Me5)([double bond, length as m-dash]C[double bond, length as m-dash]CH2)(PPh3){P(OMe)3}]BPh4 (8a) reacted with PPh3 to afford the alkenylphosphonium derivative [Os(η5-C5Me5){η1-C(H)[double bond, length as m-dash]C(H)PPh3}(PPh3){P(OMe)3}]BPh4 (18) whereas vinylidene complexes 8 and 9 reacted with water leading to the hydrolysis of the alkyne and the formation of carbonyl complexes [Os(η5-C5Me5)(CO)(PPh3){P(OR)3}]BPh4 (19, 20). The complexes were characterised by spectroscopic data (IR and NMR) and by X-ray crystal structure determination of [Os(η5-C5Me5){[double bond, length as m-dash]C[double bond, length as m-dash]C(H)p-tolyl}(PPh3){P(OEt)3}]BPh4 (9c), [Os(η5-C5Me5)(η2-O2)(PPh3){P(OMe)3}]BPh4 (10) and [Os(η5-C5Me5)(CO)(PPh3){P(OMe)3}]BPh4 (19)

SPH Modeling of Solid Boundaries Through a Semi-Analytic Approach

Abstract:This paper presents a general semi-analytic approach for modeling solid boundaries in the SPH method: boundaries are here considered as a material continuum with a suitable distribution of velocity and pressure; their contributions to each term of the SPH mass and momentum equations can be expressed in terms of a suitable integral extended to the part of the sphere of influence of the particle delimited by the boundary surface. Analytical details with reference to a slightly compressible viscous Newtonian fluid in three dimensions are given. The validity of the method is checked by comparing the obtained numerical results with available experimental data in a benchmark flow case

Forces exerted during exercises by patients with adolescent idiopathic scoliosis wearing fiberglass braces

OBJECTIVE: To quantify and compare the forces exerted by scoliosis patients in fiberglass braces during exercises usually prescribed in departments where casts are made. The exercises are intended to increase corrective forces, activate muscles, stimulate ventilation and help the patient psychologically. SETTING: Outpatient care. PATIENTS: 17 consecutive adolescent patients wearing fiberglass brace for idiopathic scoliosis. INTERVENTIONS: Exercises (kyphotization, rotation, "escape from the pad") in different positions (sitting, supine, on all fours). MAIN OUTCOME MEASURE: Pressure detected by the F-Socket System between the rib hump and the pad of the brace. RESULTS: In static and dynamic conditions, the position adopted did not alter the total pressure exerted by the brace, although the part of the sensor stimulated did vary. Kyphotization and rotation exercises produced a significant increase of pressure (+ 58.9% and +29.8%, respectively); however, the "escape from the pad" exercise, despite its name, did not produce any significant variation of pressure. CONCLUSION: Exercises in the brace allow adjunctive forces to be applied on soft tissues and through them, presumably on the spine. Different exercises can be chosen to obtain different actions. Physical exercises and sporting activities are useful in mechanical terms, although other important actions should not be overlooked

Effectiveness of complete conservative treatment for adolescent idiopathic scoliosis (bracing and exercises) based on SOSORT management criteria: results according to the SRS criteria for bracing studies - SOSORT Award 2009 Winner

<p>Abstract</p> <p>Background</p> <p>The SRS criteria give the methodological reference framework for the presentation of bracing results, while the SOSORT criteria give the clinical reference framework for an appropriate bracing treatment. The two have not been combined in a study until now. Our aim was to verify the efficacy of a complete, conservative treatment of Adolescent Idiopathic Scoliosis (AIS)according to the best methodological and management criteria defined in the literature.</p> <p>Methods</p> <p>Study Design. Retrospective study. Population. We included all AIS patients respecting the SRS inclusion criteria (age 10 years or older; Risser test 0-2; Cobb degrees 25-40°; no prior treatment; less than one year post-menarchal) who had reached the end of treatment since our institute database start in 2003. Thus we had 44 females and four males, with an age of 12.8 ± 1.6 at the commencement of the study. Methods. According to individual needs, two patients have been treated with Risser casts followed by Lyon brace, 40 with Lyon or SPoRT braces (14 for 23 hours per day, 23 for 21 h/d, and seven for 18 h/d at start), and two with exercises only (1 male, 1 female): these were excluded from further analysis. Outcome criteria. SRS (unchanged; worsened 6° or more; over 45° at the end of treatment; surgically treated; two years' follow-up); clinical (ATR, Aesthetic Index, plumbline distances); radiographic (Cobb degrees); and ISICO (optimal; minimal). Statistics. Paired ANOVA and t-test, Tukey-Kramer and chi-square test.</p> <p>Results</p> <p>Median reported compliance during the 4.2 ± 1.4 treatment years was 90% (range 5-106%). No patient progressed beyond 45°, nor was any patient fused, and this remained true at the two-year follow-up for the 85% that reached it. Only two patients (4%) worsened, both with single thoracic curve, 25-30° Cobb and Risser 0 at the start. We found statistically significant reductions of the scoliosis curvatures (-7.1°): thoracic (-7.3°), thoracolumbar (-8.4°) and lumbar (-7.8°), but not double major. Statistically significant improvements have also been found for aesthetics and ATR.</p> <p>Conclusion</p> <p>Respecting also SOSORT management criteria and thus increasing compliance, the results of conservative treatment were much better than what had previously been reported in the literature using SRS criteria only.</p

Cohort profile: The Observational cohort for the study of DOlutegravir in Antiretroviral Combination REgimens (ODOACRE)

The Observational cohort for the study of DOlutegravir in Antiretroviral Combination REgimens (ODOACRE) cohort was established in Italy in 2016 to evaluate the overall efficacy and tolerability of dolutegravir (DTG)-based antiretroviral (ARV) regimens in clinical practice

Brace technology thematic series - The Sforzesco and Sibilla braces, and the SPoRT (Symmetric, Patient oriented, Rigid, Three-dimensional, active) concept

<p>Abstract</p> <p>Background</p> <p>Bracing is an effective strategy for scoliosis treatment, but there is no consensus on the best type of brace, nor on the way in which it should act on the spine to achieve good correction. The aim of this paper is to present the family of SPoRT (Symmetric, Patient-oriented, Rigid, Three-dimensional, active) braces: Sforzesco (the first introduced), Sibilla and Lapadula.</p> <p>Methods</p> <p>The Sforzesco brace was developed following specific principles of correction. Due to its overall symmetry, the brace provides space over pathological depressions and pushes over elevations. Correction is reached through construction of the envelope, pushes, escapes, stops, and drivers. The real novelty is the drivers, introduced for the first time with the Sforzesco brace; they allow to achieve the main action of the brace: a three-dimensional elongation pushing the spine in a down-up direction.</p> <p>Brace prescription is made plane by plane: frontal (on the "slopes", another novelty of this concept, i.e. the laterally flexed sections of the spine), horizontal, and sagittal. The brace is built modelling the trunk shape obtained either by a plaster cast mould or by CAD-CAM construction. Brace checking is essential, since SPoRT braces are adjustable and customisable according to each individual curve pattern.</p> <p>Treatment time and duration is individually tailored (18-23 hours per day until Risser 3, then gradual reduction). SEAS (Scientific Exercises Approach to Scoliosis) exercises are a key factor to achieve success.</p> <p>Results</p> <p>The Sforzesco brace has shown to be more effective than the Lyon brace (matched case/control), equally effective as the Risser plaster cast (prospective cohort with retrospective controls), more effective than the Risser cast + Lyon brace in treating curves over 45 degrees Cobb (prospective cohort), and is able to improve aesthetic appearance (prospective cohort).</p> <p>Conclusions</p> <p>The SPoRT concept of bracing (three-dimensional elongation pushing in a down-up direction) is different from the other corrective systems: 3-point, traction, postural, and movement-based. The Sforzesco brace, being comparable to casting, may be the best brace for the worst cases.</p